Over the decades since electronic computers were first invented, office practices have become dominated by them and information handling is now very heavily based in the electronic domain of the computer. The vast majority of documents are prepared, adapted, stored and even read in electronic form on computer display screens. Furthermore, in parallel to this, the computer interface technology has advanced from there being a predominantly physical interface with the computer using punched cards, keypads or keyboards for data entry—to the extensive present-day reliance on use of cursor moving devices such as the mouse for interacting with the screen-displayed essentially electronic interface known as the Graphical User Interface (GUI) that is in use universally in applications such as Windows®. The Graphical User Interface can be regarded as a virtual interface comprising operator key icons that replace the pushbutton keys of a physical keyboard.
The drive towards handling documents electronically and also representing hardware computer interfaces in a predominantly electronic form has been relentless since, amongst other obvious benefits, software implementations of hardware occupy no space and may be many orders of magnitude cheaper to produce. Nevertheless, electronic versions of documents and virtual interfaces do not readily suit the ergonomic needs of all users and uses. For some tasks, reading included, paper-based documents are much more user friendly than screen-based documents. Hard copy paper versions of electronic documents are still preferred by many for proof-reading or general reviews, since they are of optimally high resolution and flicker-free and less liable to give the reader eye-strain, for example.
In recent years the Xerox Corporation have been in the vanguard of developments to better integrate beneficial elements of paper based documents with their electronic counterpart. In particular they have sought to develop interface systems that heighten the level of physical interactivity and make use of computers to enhance paper-based operations.
Their European patent EP 0,622,722 describes a system in which an original paper document lying on a work surface is monitored by an overhead camera linked to a processor/computer to monitor the user's interaction with text or images on the paper document. An action such as pointing to an area of the paper document can be used to select and manipulate an image taken by the camera of the document and the image or a manipulated form of it is then projected back onto the work surface as a copy or modified copy. The Xerox interactive copying system is suited to this rôle but is not optimally compact, cost efficient and well adapted for other paper-based activities than document copying and modification.
One desirable type of paper-based interaction would be to print out a list of Internet search results and read through these on paper and to then use the printed paper to select an Internet page to be printed or displayed by simply pointing at the relevant area on the printed page. Aspects of such a use for paper-based computer interaction are further discussed in the present applicant's co-pending UK patent application.
Existing systems such as the aforementioned Xerox interactive copying system are not suited to such uses.